128 Questions
What is the characteristic of the movement of bacteria that exhibit gliding motility?
It is a movement in the direction of its long axis on a surface.
What is the function of axial filaments in spirochetes?
They impart rapid motility to the spirochete.
What is the term used to describe the movement of bacteria towards or away from substances in their environment?
Chemotaxis
What is the characteristic of the movement of bacteria that do not have a specific direction?
It is a random movement.
What is the name of the structure that is found only in spirochetes and is involved in their motility?
Axial filaments
What is the purpose of chemotaxis in bacteria?
To move towards or away from substances in their environment.
What is the term used to describe the movement of bacteria that is non-random and directed towards or away from substances?
Chemotaxis
What is the characteristic of the movement of bacteria that use flagella to move?
It is a flagellated movement.
What is the term used to describe the movement of bacteria that do not have a specific direction of movement?
Random movement
What is the purpose of axial filaments in spirochetes?
To impart rapid motility to the spirochete.
What is an inorganic nutrient?
An atom or simple molecule that contains a combination of atoms other than carbon and hydrogen
What is the central component of biological macromolecules?
Carbon
What is the difference between inorganic and organic nutrients?
Inorganic nutrients do not contain carbon and hydrogen, while organic nutrients do
What is an example of an inorganic compound?
Magnesium sulfate
What is the role of hydrogen in biological systems?
It is a major component of macromolecules
What is the source of carbon in biological systems?
From both organic and inorganic sources
What is a characteristic of micronutrients?
They are metal ions that frequently serve as cofactors for enzymes
What is an example of a gas that is an inorganic compound?
All of the above
What is the difference between organic and inorganic macromolecules?
Organic macromolecules contain carbon and hydrogen, while inorganic macromolecules do not
What is the natural reservoir of inorganic compounds?
Mineral deposits and bodies of water
What is the relationship between the carbon atoms in methane?
They are single bonded
What is the main difference between the hydrocarbon chain and the hydrocarbon ring?
The chain is linear and the ring is cyclic
What is the general formula for the hydrocarbon chain?
CnH2n+1
What is the general formula for the hydrocarbon ring?
CnH2n-1
What is the name of the process by which a hydrocarbon chain is converted into a hydrocarbon ring?
Cyclization
What is the name of the process by which a hydrocarbon is broken down into smaller molecules?
Catalytic cracking
What is the main characteristic of a saturated hydrocarbon?
It has a single bond between the carbon atoms
What is the main characteristic of an unsaturated hydrocarbon?
It has a double bond between the carbon atoms
What is the term for the movement of bacteria towards or away from light?
Phototaxis
What is the role of the catalyst in the process of catalytic cracking?
To provide a surface for the reaction to occur on
What is the main advantage of catalytic cracking over other methods of cracking?
It requires a lower temperature and pressure
Which of the following statements is TRUE about bacteria that exhibit positive phototaxis?
They move towards light
What is the term for the essential elements required by microorganisms for growth?
Microbial Nutrition
Which of the following is an example of microbial movement?
Phototaxis
What is the term for the movement of bacteria towards or away from chemicals?
Chemotaxis
Which of the following statements is FALSE about bacteria that exhibit negative phototaxis?
They move towards light
What is the term for the process by which bacteria move towards or away from a stimulus?
Taxis
Which of the following is NOT an example of microbial movement?
Microbial Growth
What is the term for the movement of bacteria towards or away from oxygen?
Aerotaxis
Which of the following is an example of a stimulus that can affect microbial movement?
All of the above
What percentage of a microbial cell's dry weight is made up of a few major elements?
95%
Which of the following is NOT a macronutrient?
Zinc
What is the primary role of carbon in living cells?
Structural component
Which of the following is an essential micronutrient?
All of the above
What is the process by which chemical substances called nutrients are acquired from the environment and used in cellular activities?
Nutrition
Which of the following elements is NOT a major component of microbial cells?
Chlorine
What is the term for the study of the chemical composition of cells?
Biochemistry
Which of the following is a function of macronutrients?
All of the above
What is the term for the process by which cells use nutrients to synthesize new molecules?
Anabolism
Which of the following elements is required in smaller amounts, but is still essential for cellular activities?
Zinc
What is the main function of nitrogen in the cell?
To synthesize proteins and amino acids
What is the source of phosphorus in the cell?
Phosphate (PO4)
What is the role of sulphur in the cell?
To synthesize proteins and vitamins
What is the byproduct of nitrirocation reaction?
NH3
What is the source of nitrogen in the cell?
N2
What is the role of ATP in the cell?
To provide energy for cellular processes
What is the result of nitrogen fixation?
Production of NH3
What is the primary source of carbon for autotrophic organisms?
Inorganic CO2
What is the role of copper in the cell?
To act as a cofactor in enzyme reactions
What role does hydrogen play in the biochemistry of cells?
Forming hydrogen bonds, maintaining pH, and serving as the source of free energy
What is the function of potassium in microbial metabolism?
Protein synthesis and membrane function
What is the source of sulphur in the cell?
Sulphates and sulphides
What is the role of magnesium in the cell?
To act as a cofactor in enzyme reactions
What is the function of oxygen in organic compounds?
Playing an important role in the structural and enzymatic functions of the cell
Which mineral ion is important for certain types of cell transport?
Sodium
What is the importance of nitrogen in the synthesis of proteins and nucleic acids?
It is necessary for the synthesis of proteins and nucleic acids
What is the role of calcium in microbial metabolism?
Stabilization of cell walls and endospores
Which type of organism is nutritionally dependent on other living things?
Heterotrophic
What is the process by which some bacteria and algae convert nitrogen into a usable form?
Nitrogen fixation
What is the classification of bacteria based on nutritional requirement?
According to carbon source
What is the role of hydrogen in the biochemistry of cells?
Forming hydrogen bonds, maintaining pH, and serving as the source of free energy
Which mineral ion is a component of chlorophyll?
Magnesium
What is the importance of oxygen in the biochemistry of cells?
It plays an important role in the structural and enzymatic functions of the cell
What is the role of nitrogen in the biochemistry of cells?
It is necessary for the synthesis of proteins and nucleic acids
What is the role of iron in microbial metabolism?
Component of cytochrome proteins
Which mineral ion is an essential regulatory element for eukaryotic genetics?
Zinc
What is the importance of hydrogen in the synthesis of proteins and nucleic acids?
It is used in the process of hydrogen bonding
What is the classification of bacteria based on energy source?
Phototrophic, chemotrophic, or organotrophic
What is the role of oxygen in the process of oxidation-reduction reactions?
It serves as the source of free energy in oxidation-reduction reactions
What is the importance of nitrogen in the process of nitrogen fixation?
It is converted into a usable form through nitrogen fixation
What are the three main groups of growth factors that can be identified?
Amino acids, purines, and pyrimidines
What is the role of amino acids in growth factors?
Required for nucleic acid synthesis
Why are vitamins important for growth factors?
They are needed for the growth and development of cells
What is the term used to describe the movement of bacteria towards or away from substances in their environment?
Chemotaxis
What is the characteristic of the movement of bacteria that exhibit gliding motility?
They move without the use of flagella
What is the purpose of axial filaments in spirochetes?
To aid in the movement of the bacteria
What is the term used to describe the movement of bacteria that do not have a specific direction?
Random movement
What is the characteristic of the movement of bacteria that use flagella to move?
They move with the use of flagella
What is the term used to describe the movement of bacteria towards or away from substances in their environment?
Chemotaxis
What is the purpose of chemotaxis in bacteria?
To move towards or away from substances
What type of microbes obtain energy from the oxidation of chemical compounds?
Chemotrophic
Which of the following microbes use light energy and CO2 as a carbon source?
Photolithotrophic autotrophs
What type of microbes reduce inorganic substances as an electron source?
Lithotrophs
Which of the following microbes extract electrons or hydrogen from organic compounds?
Organotrophs
What is the term used to describe microbes that use light as an energy source?
Phototrophs
Which of the following microbes use the oxidation of chemical compounds as an energy source?
Chemotrophs
What type of microbes obtain energy from the oxidation of inorganic substances?
Lithotrophs
Which of the following microbes use organic compounds as a carbon source?
Organotrophs
What is the term used to describe microbes that obtain energy from light and use CO2 as a carbon source?
Photolithotrophic autotrophs
Which of the following microbes obtain energy from the oxidation of organic compounds?
Organotrophs
What is the main importance of growth in microbial control, infectious disease, and biotechnology?
Increase in population size
What is the definition of growth in unicellular microorganisms?
Increase in population size through cell division
What is the result of cell growth and multiplication in microbial populations?
Increase in biomass
What is the term used to describe the increase in population size through cell growth and multiplication?
Growth
What is the role of growth in microbial control?
To reduce population size
What is the significance of growth in biotechnology?
All of the above
What is the consequence of uncontrolled growth in microbial populations?
Increased risk of infectious disease
What is the role of cell growth and multiplication in microbial populations?
To increase population size
What is the result of increased growth in microbial populations?
Increased biomass
What is the significance of growth in infectious disease?
Increasing the risk of infection
What is the role of hydrogens in biosynthesis?
Carbon source
What is the process by which microorganisms synthesize their own food?
Autotrophy
What is the term used to describe microorganisms that can synthesize their own food?
Autotrophs
What is the role of CO2 in microbial growth?
Carbon source
What is the term used to describe the study of microbial growth?
Microbial growth kinetics
What is the requirement for microbial growth?
Nutrients and environmental factors
What is the result of microbial growth?
Increase in both cell size and number
What is the term used to describe the movement of microorganisms towards or away from substances?
Chemotaxis
What is the role of electrons in microbial growth?
Electron donor
What is the term used to describe the synthesis of new cell components?
Anabolism
What is the primary method of cell division in bacteria?
Binary fission
During binary fission, what is the role of the transverse septum?
It divides the cell into two daughter cells
What is the result of repeated binary fission in bacteria?
An increase in population size
What is the characteristic of the process of binary fission?
It involves the formation of two identical daughter cells
What is the role of the parent cell in binary fission?
It divides into two daughter cells
What is the significance of binary fission in bacteria?
It is a mechanism of asexual reproduction
What is the advantage of binary fission over other forms of cell division?
It is a rapid and efficient mechanism of asexual reproduction
What is the relationship between the daughter cells formed during binary fission?
They are genetically identical
Study Notes
Bacterial Movement
- Bacteria exhibit generally random movements, with no single direction of movement more likely than others
- Some bacteria exhibit gliding motility, crawling over surfaces through waves of contraction in the cytoplasm
- Gliding is defined as the movement of a non-flagellated cell in the direction of its long axis on a surface
- Axial filaments found in spirochetes consist of protein fibrils wound spirally around the organism and attached at the two poles
- These axial filaments are located beneath the membrane and function to impart rapid motility to the spirochete
Chemotaxis
- Bacteria can move toward or away from substances in their environment through a non-random process called chemotaxis
- Bacteria with rotary motors powered by proton or sodium gradients can switch between clockwise and counterclockwise rotation
- This movement is believed to occur by using energy to make one of the rings in the cell membrane rotate relative to the others
- When the rings are linked together, they rotate in the opposite direction of the clock, causing the bacteria to run or tumble
Phototaxis
- Some bacteria can move toward or away from light, a response called phototaxis
- Bacteria that move toward light exhibit positive phototaxis, while those that move away exhibit negative phototaxis
Microbial Nutrition
-
Microorganisms require several essential elements for growth and biosynthesis of cellular components
-
The major elements are carbon, nitrogen, oxygen, hydrogen, sulfur, phosphorus, magnesium, potassium, sodium, calcium, and iron
-
Carbon is the central component of biological macromolecules and can be derived from organic or inorganic sources
-
Hydrogen is a major element in organic and inorganic compounds, including water, salts, and gases
-
Inorganic nutrients are atoms or simple molecules containing elements other than carbon and hydrogen, found in mineral deposits, water, and the atmosphere
-
Organic nutrients contain carbon and hydrogen atoms and are usually products of living organisms, ranging from simple molecules to large polymers
-
Micronutrients are predominantly metal ions that often serve as cofactors for enzymes### Organic and Inorganic Carbon Sources
-
Some organisms require organic carbon, while others can use inorganic carbon (CO2) as a carbon source
-
Autotrophs can convert CO2 into organic compounds, so they are not dependent on other organisms for their carbon
-
Heterotrophs must obtain their carbon in organic form, as they cannot synthesize it from inorganic sources
Hydrogen
- Hydrogen is a key element in all organic compounds and many inorganic compounds (water, H2S, CH4)
- Microbes use and produce hydrogen
- Hydrogen plays important roles in cell biochemistry:
- Maintaining pH
- Forming hydrogen bonds between molecules
- Serving as the source of free energy in redox reactions
Oxygen
- Oxygen is a major component of organic compounds like carbohydrates, lipids, nucleic acids, and proteins
- Oxygen plays important structural and enzymatic roles in cells
- Oxygen is also found in inorganic salts like sulfates, phosphates, and nitrates
Nitrogen
- Nitrogen is required for synthesis of proteins, nucleic acids (DNA, RNA), and important molecules like ATP
- Some bacteria and algae can utilize inorganic nitrogen sources (N, NO2, NH3)
- A few prokaryotes can convert atmospheric N2 into usable compounds through nitrogen fixation
Sulfur
- Sulfur is required for synthesis of proteins and vitamins
- In some organisms, it is involved in cellular respiration and photosynthesis
- Sulfur may be derived from sulfur-containing amino acids (methionine, cysteine), sulfates and sulfides
Phosphorus
- The main inorganic source of phosphorus is phosphate (PO4), derived from phosphoric acid (H3PO4)
- Phosphate is a key component of nucleic acids and is essential for cell genetics
- Metals like copper, iron and magnesium are required as enzyme cofactors
Growth Factors
- Many microorganisms cannot synthesize certain organic compounds necessary for growth
- These are termed growth factors, including amino acids, purines, pyrimidines, and vitaminsHere are the study notes for the provided text:
Autotrophs and Heterotrophs
- Autotrophs: organisms that produce their own food using energy from the environment (e.g., sunlight, water, carbon dioxide)
- Examples: phototrophs, chemotrophs
- Heterotrophs: organisms that cannot produce their own food and need to consume other organisms or organic matter to survive
- Examples: animals, fungi, some bacteria
Microbial Growth
- Microbial growth occurs when microbes are provided with nutrients and the required environmental factors
- Growth takes place on two levels:
- Cell growth: increase in cell size
- Population growth: increase in the number of cells
- Growth takes place on two levels:
- Importance of microbial growth:
- Microbial control: understanding how microbes grow helps in controlling their growth and preventing infection
- Infectious diseases: understanding how microbes grow helps in understanding the progression of infections
- Biotechnology: understanding how microbes grow helps in harnessing their potential for biotechnological applications
Binary Fission
- Binary fission: a type of cell division that occurs in bacteria, where one cell divides into two daughter cells
- Process of binary fission:
- The parent cell enlarges
- The chromosome is duplicated
- A central transverse septum forms, dividing the cell into two daughter cells
- Each daughter cell receives a copy of the chromosome
- The process is repeated by each new daughter cell, leading to an increase in the population
Cell Division
- Cell division is a critical process in microbial growth
- Allows for the increase in cell number and biomass
- Ensures the continuation of the species
- Importance of understanding cell division:
- Understanding how microbes divide helps in understanding their growth and behavior
- Has implications for fields such as medicine, agriculture, and biotechnology
Learn about the different ways bacteria move, including random movements, gliding motility, and the role of axial filaments in spirochetes.
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